bolt on hybrid?

Interesting idea:"A cheap bolt-on kit will one day be able to turn most ordinary cars into fuel-sipping plug-in hybrids, US researchers say.Engineering technology students at the Middle Tennessee State University have fitted a 20-year-old Honda Accord wagon with a retrofit plug-in hybrid system that powers the front wheels using the conventional petrol engine, and a pair of electric hub motors hidden inside the rear wheels.Users are then able to plug the hybrid car into an ordinary power point to charge up a set of lithium-ion batteries mounted in the wagon’s load space.The batteries in turn feed electricity into the hub motors to provide low-speed power that is able to help the conventional petrol engine accelerate - the most fuel-hungry part of driving.The bolt-on kit was developed in recognition of the fact that many drivers in the US only travelled about 70 kilometres a day at speeds below about 70km/h.According to researchers, the in-wheel electric motors provide about 270Nm of torque - the equivalent pulling power of a 1.6-litre turbocharged four-cylinder diesel engine - and help to slash the car’s fuel bill in half.Even better, researchers say the system currently costs roughly $3000, about twice the price of converting a car to run on LPG, but costs should come down as battery technology improves and the suitcase-sized bank of batteries becomes much smaller.According to the university, the big benefit of the retrofit system is that it does not require any modification to the suspension or drivetrain to use it, bolting on directly over the existing parts.MTSU says the university is now looking for a business partner to help it commercialise the concept."

This project sounds like it was fun and a great learning experience for some engineering undergrads, but I don't see this particular idea making a successful transition to the commercial world. Getting two different propulsion systems to operate seamlessly and reliably on a single automotive drivetrain under real world conditions is incredibly difficult. I would also question the claimed $3000 cost premium for retrofitting such a system.

In reality, how much of a market is there for a $3000+ do-it-yourself hybrid retrofit kit for 20-year-old Honda Accords that will likely never save enough in fuel costs to pay for itself? A more practical project for these MTSU engineering undergrads to pursue (and one that would have actual commercial value) would have been an automotive fuel system retrofit and home refueling system that allows use of residential natural gas. Most US homes already have natural gas service. Residential natural gas prices are currently low, and are getting lower. Natural gas supplies are very plentiful and will be so for many years to come. And most importantly, residential natural gas is not subject to the 25% or so federal/state fuel taxes on gasoline or diesel.

This project sounds like it was fun and a great learning experience for some engineering undergrads, but I don't see this particular idea making a successful transition to the commercial world. Getting two different propulsion systems to operate seamlessly and reliably on a single automotive drivetrain under real world conditions is incredibly difficult. I would also question the claimed $3000 cost premium for retrofitting such a system.

Really? There's a lot of hybrid cars on the roads you know. Of course, retrofitting may be tricky compared to something designed as a hybrid from the ground up, but "incredibly difficult"?

In reality, how much of a market is there for a $3000+ do-it-yourself hybrid retrofit kit for 20-year-old Honda Accords that will likely never save enough in fuel costs to pay for itself? A more practical project for these MTSU engineering undergrads to pursue (and one that would have actual commercial value) would have been an automotive fuel system retrofit and home refueling system that allows use of residential natural gas. Most US homes already have natural gas service. Residential natural gas prices are currently low, and are getting lower. Natural gas supplies are very plentiful and will be so for many years to come. And most importantly, residential natural gas is not subject to the 25% or so federal/state fuel taxes on gasoline or diesel.

Point of the system would be that it could in theory be fitted to basically any car, not just old Honda Accords.

I think it's a great idea for people who can't afford a new car. Would be much cheaper and easier than a full EV conversion and wouldn't "waist" the fully functional IC drivetrain in the car, widening the choice of cars dramatically. If it works commercially will of course depend on the economics of it, but I think you're too pessimistic. Things will not stand still.

Agree. I don't see huge difficulties in the control system - especially if the IC drivetrain is an auto. A University team would be more than capable of sorting that out. The control algorithm could include a range of energy-saving modes - even a highway mode which recharges the batteries from the IC engine operating near its efficiency peak and using the hub motors as generators. When the batteries are fully charged, switch off the IC and cruise on eletric until the batteries need recharging.

As for market, I know a lot of people who would jump at this. $3k installed could translate to about $2k in DIY kit form. Plenty of tinkerers (myself included) would jump at that.

Wheel motors are fairly expensive, say 1000 each for a 10 kW unit (eventually). 20 kW motor controller, depends on the technology, anything from ? bucks to 10000 or more. then there is the batteries. The expensive bit in the motor controller are the output power FETs, where there is a tradeoff between efficiency and cost.

I camn think of several reasons not to do this. The unsprung weight has just doubled, meaning the shocks at the very least will not be up for it,, and the car will drive like a pig. You are losing most of your cargo space to batteries, batteries that have to be replaced on a semi regular occasion. Plus said batterys are bloody heavy so you have just dropped your fuel economy drastically. The insurance, I doubt any company would give it. An overloaded poorly sprung car is an accident waiting to happen. And no insurance no drive!
Buy a Prius, though that still has most of the above pitfalls but they will insure it, for an added premium.

local car club had an economy rally over past weekend and the figures are just in. The road course was 116km over outer suburban and minor country roads, usually at 60-80kph. Economy recorded thus in l/100km:

local car club had an economy rally over past weekend and the figures are just in. The road course was 116km over outer suburban and minor country roads, usually at 60-80kph. Economy recorded thus in l/100km:

Having just competed in two economy runs in the last year or so, and many back in the day, I know what it takes to win these. Acting like you are actually driving on a day-to-day basis, driving to a purpose is just not going to get these results.

Having said that, it is fair to say that there are options out there that will give you and me a lot better economy than we are (me certainly, you probably) getting now - if we value that economy high enough to accept what it takes to get it.

I had the distinct misfortune of getting a Camry hybrid as a rental car last year. It fits that description perfectly. If you just had a few passengers in the car, it wasn't that bad. As soon as you added luggage to the trunk, the car transformed into a white knuckle factory. It desperately wanted to be in "The Other Lane". Every slight bump or ripple in the pavement made the car wag and yaw like a tire had just blown out. I'm not a vehicle dynamics expert, but it felt to me like the front and rear roll response were 180 degrees out of phase which made each end of the car try to steer in opposite directions.

It was worse than driving an old 911. Way worse. The 911 only has bad manners when provoked. The Camry hybrid has bad manners all the time.

Having just competed in two economy runs in the last year or so, and many back in the day, I know what it takes to win these. Acting like you are actually driving on a day-to-day basis, driving to a purpose is just not going to get these results.

Having said that, it is fair to say that there are options out there that will give you and me a lot better economy than we are (me certainly, you probably) getting now - if we value that economy high enough to accept what it takes to get it.

I have done the odd economy run in my day. A 307 [with only 15 cam lobes!!] HK Premier with 1/2 a ton of bricks on board got 34mpg . The event was for ton MPG by the way. That was through the Adelaide hills. The worst ton MPG on that day was a 750 Yamaha!! Closely followed by a Mini.Or 38.8 mpg from a 186 Kingswood another time. The last one was 40.1mpg from an ED Falcon. These were straight economy runs.And the MPG just continues the tradition.

My father averaged 34 mpg in a 186 Holden auto from Adelaide to Brisbane 30 years ago when the roads were not quite so good.Watching fuel readout on trip computers is interesting. A 5 litre Fairlane sat on 7 litres a 100km for a lot of miles towing a racecar. Unfortunatly it did not average anywhere near that. Those pesky hills, pasing and etc! But that was 3.5 tonne of car trailer and load.Though that car was better than the 6 cyl one I had used around that time and worked a bit easier.

A friend used more fuel doing Adelaide melbourne in her 1.5 auto Daepoo than we did in my 4 litre Falcon a few weeks before.I have heard a similar story with 2 couples doing a similar trip, 1 in a Prius and one in a Mazda 3. The Mazda used less fuel!And obviously drove far nicer.Plus the Top Gear clip with a Prius v a v8 BMW on the test track, the Prius used far more fuel trying to keep up.Why would anyone ever want a expensive to run and maintain and insure hybrid?

I'm not surprised by the Falcon, if it was a model between 95 and 2002. We had a feature called lean cruise, basically if you were driving at ~100 kph without much change the strategy sat there leaning out the mixture until the knock sensor said enough. Eventually the Feds caught on and stopped us (high NOx).

A hybrid cannot operate at a better “BSFC” (Kg of fuel / KWh of provided energy) than the peak BSFC of the internal combustion engine it is based on.

The hybrid technology is based totally on the poor BSFC of the internal combustion engine outside a relatively narrow range of revs and loads. It charges the battery with the engine operating at the efficient revs / loads and then uses the stored energy to move the vehicle. The inevitable loss of energy (kinetic energy to electric energy, then electric energy to chemical energy into the battery, then chemical energy to electric energy, then electric energy to kinetic energy to move the car for as long as the ICE is turned off) is preferable as compared to the case with the engine operating outside its efficient rev / load range.

An ideal internal combustion engine able to keep the same good thermal efficiency (say 40% which means a BSFC of about 0.210 Kg/KWh) along the whole operating range of revs and loads is not a good base for applying the hybrid technology. With the energy loss during the multiple transformations of energy from the internal combustion engine to, initially, electric energy, then to chemical energy, then back to electric energy and finally to kinetic energy) the hybrid version is difficult to achieve a, say, more than 35% total “BSFC” (0.240 Kg/KWh). Besides the additional cost and complication, the fuel economy and the emissions are way worse as compared to the original car with the “ideal” engine.

The Diesel engine is closer to the abovementioned “ideal” internal combustion engine. Compare the Volvo 1600cc Diesel with the Toyota Prius. Similar weight and size, similar fuel consumption / emissions in the official urban and extra urban cycles. Is there something that justifies the price difference between the two cars?

Some engine makers try another way: to expand the efficient rev / load range of their conventional gasoline engines. And the results are quite good: Mazda with their SkyAxtive gasoline engines (constant compression ratio at 14:1, limited Miller cycle, turbocharged),Nissan with their Micra 1.2 DIG-S (constant compression ratio at 13:1, limited Miller cycle, supercharged),achieve near to hybrid fuel efficiency without the hybrid cost.In order to keep the operation of their engines optimized at all conditions, a variable compression ratio – as at http://www.pattakon....pattakonVCR.htm - would be way better (the peak power of the Mazda SkyActive would double if the compression ratio could drop from 14:1 to 8:1 when plenty of power is necessary). Also a more variable VVA capable for an unlimited Miller cycle – as at http://www.pattakon....ttakonHydro.htm - would be way better, too.

Consider the case of a sport car having a powerful V-8 engine at the one side of the primary shaft of its gearbox (in the place of the 11, Fig 21), and a small green engine (like the single cylinder full balanced PatPOC or PatOP, or like the Fiat 500 TwinAir) at the other end of gearbox primary shaft (in the place of the 10, Fig 21).

The car can go downtown (and anywhere else the driver likes to go economically and environmentally) using its small green engine. With the coolant from the small engine circulating into the big engine, to keep it warm, the V-8 is ready, any moment, to power the car (with or without the assistance of the green engine). The vehicle is way more reliable and cheap-to-run and cheap-to-maintain and green. The big engine design becomes more uncompromised. And because it doesn’t need to operate at conditions not matching its character, the big engine will last longer (it isn’t rare: an expensive sport car struggling to idle in the bottleneck, with the rest drivers shutting their car windows to keep the noise out). Compare this solution to the new sport hybrid cars the sport-car makers launch, one by one, in their effort to comply with the present and future emission regulations. Judging from the 95 gr CO2 / Km, in the combined European cycle, of the 1030Kp heavy Fiat 500 TwinAir, the sport car, any sport car, can be – according the present regulations – as green and fuel efficient as the best hybrid cars, without batteries, without electromotors, without high tech control and without high cost.

Putting a small / efficient internal combustion engine at the free side of the primary shaft of the gearbox of the 20-year-old Honda Accord wagon of the Middle Tennessee State University (instead of the bolt on hybrid system) seems as a better solution. At light loads the small engine is used, at heavier loads the original engine is used, for peak power both engines are used, in case the one engine fails, the car continuous with the other.

Consider the case of a sport car having a powerful V-8 engine at the one side of the primary shaft of its gearbox (in the place of the 11, Fig 21), and a small green engine (like the single cylinder full balanced PatPOC or PatOP, or like the Fiat 500 TwinAir) at the other end of gearbox primary shaft (in the place of the 10, Fig 21).

Bolt on hybrid units could be a reality if the goverments demand a standarised motor room for a surtain type of car class.

While that might appeal to the Stalinists amongst us, modern car design uses the free space in a design more efficiently than a Civil Servant could ever do. So you are forcing /all/ cars to be less efficient so that some cars can have a hybrid engine.

On the matter of bolt-on hybrids, I always thought the GM BAS approach had interesting possibilities. Motor-generator supplies drive through the gas engine's serpentine belt.

Now, I don't propose that any bolt-on hybrid system could truly pay its way in fuel savings to the consumer at the moment, but this way seems more realistic than some other systems, especially in terms of unit cost, install-ability, and range of applications.

The setup below is Gen 1 as used on the 2007 Saturn, etc. Gen II aka eAssist is available on the 2012 Buick. One generation newer motor and battery technnology, essentially.

BAS is ok for a light hybrid although I prefer the flywheel mounted systems. But if you've gone that far you might as well put it on the axle side of the clutch and allow full electric drive. The advantage of any of these upsteam solutions compared with wheel motors is that they exploit the axle ratio, allowing for a small high speed motor, and you only need one motor, and you don't have expensive items stuck in the wheels.

A hybrid cannot operate at a better “BSFC” (Kg of fuel / KWh of provided energy) than the peak BSFC of the internal combustion engine it is based on.

The hybrid technology is based totally on the poor BSFC of the internal combustion engine outside a relatively narrow range of revs and loads. It charges the battery with the engine operating at the efficient revs / loads and then uses the stored energy to move the vehicle. The inevitable loss of energy (kinetic energy to electric energy, then electric energy to chemical energy into the battery, then chemical energy to electric energy, then electric energy to kinetic energy to move the car for as long as the ICE is turned off) is preferable as compared to the case with the engine operating outside its efficient rev / load range.

An ideal internal combustion engine able to keep the same good thermal efficiency (say 40% which means a BSFC of about 0.210 Kg/KWh) along the whole operating range of revs and loads is not a good base for applying the hybrid technology. With the energy loss during the multiple transformations of energy from the internal combustion engine to, initially, electric energy, then to chemical energy, then back to electric energy and finally to kinetic energy) the hybrid version is difficult to achieve a, say, more than 35% total “BSFC” (0.240 Kg/KWh). Besides the additional cost and complication, the fuel economy and the emissions are way worse as compared to the original car with the “ideal” engine.

Manny, you have neglected to mention the additional advantages of regenerative braking and the potential for "plug in" as in the system described in the OP.

Yep, and I heard of someone who smoked all their life and lived to 100.

OTOH, I personally do a regular commute in either my 4 litre Falcon or my Daughter's 1.6 litre Hyundai. The Hyundai uses 1/2 the fuel for the same trip.

Not on open road highway driving, there is very little difference, and as I said the Falcon was more economical than the Daepoo. She is a on and off the throttle driver which is not economical, but she drove half the way on our trip.Even metro [not city ] driving there is often not a huge difference between the asthmatic 4 and the lazy big 6. But heavy stop start driving is what kills the Fords economy.

Not on open road highway driving, there is very little difference, and as I said the Falcon was more economical than the Daepoo. She is a on and off the throttle driver which is not economical, but she drove half the way on our trip.Even metro [not city ] driving there is often not a huge difference between the asthmatic 4 and the lazy big 6. But heavy stop start driving is what kills the Fords economy.

My Ford (1996 EF II 4.0 auto) does 9 L/100km on the highway and the Hyundai (2001 Accent 1.6 manual) does 5.Red Book says 7.4 for the Ford (what a joke, mine is better than average) and 5.0 for the Hyundai. Doesn't matter which way you look at it there is a big difference.

If your Daewoo uses anywhere near the fuel of your Ford, one or more of the following applies:1. They are being driven differently (as you suggest)2. The Daewoo has a problem3. TheFord is a freak4. The Daewoo is a bad model which is not representative of its class

While that might appeal to the Stalinists amongst us, modern car design uses the free space in a design more efficiently than a Civil Servant could ever do. So you are forcing /all/ cars to be less efficient so that some cars can have a hybrid engine.

Then there will be no bolt on hybrid systems that fits across brands.

Im not really buying the less efficient due to packaging.

Designing the car around the standard parts is something they allready kinda do. VW Golf platform is a good example that gets used across different models. Same with their motors.

Standardisation is efficient.

Or should we reverse to when we had unice bolt/screw threads pr railroad company?

Im not talking about ONE type of hybrid unit. But a standard series kinda like when they have 1.6L to 2.5L options today.

Having standardised batteries or elements of the batteries. makes a recycle factory cheaper.

Lots of gains. Some challenges. The hybrid units will go trough a evolution like most others. The gain is that newer will probably be smaller and thus they will not be a challenge to fit in a older car.

Is standarisation (prob miss spelled) likely to such a high degree?

Naa. not likely. Companies allready cooperate across brands and the politicians would rather probably impose efficiency demands. Kinda like thee emissions we have today.

Efficiency demands could lead manufacturers down this ally. But regardless of option thats decades ahead if ever.

My Ford (1996 EF II 4.0 auto) does 9 L/100km on the highway and the Hyundai (2001 Accent 1.6 manual) does 5.Red Book says 7.4 for the Ford (what a joke, mine is better than average) and 5.0 for the Hyundai. Doesn't matter which way you look at it there is a big difference.

If your Daewoo uses anywhere near the fuel of your Ford, one or more of the following applies:1. They are being driven differently (as you suggest)2. The Daewoo has a problem3. TheFord is a freak4. The Daewoo is a bad model which is not representative of its class

So called econo boxes often are not, and never will be. That is a fact of life but people always think that a 1.5 will use 1/4 the amount of petrol than a 4 litre. Which will never be the case as they will always be far less efficient. City driving a smaller engine will use less fuel ofcourse but probably 30% less, still making them very ineficient.Late 70s early 80s people went and bought 4 cyl familys cars, Sigmas, Coronas, Cortinas and the like. Then put autos and aircond etc. They used more petrol and carried less people comfortably than the full size Fords and Holdens etc.And were traded in again on full size cars in a year or two.And with the Daewoo, the family 4 with an auto, aircond and power steering pushing a big tall unairdynamic box is an asthmatic shit box and drinks fuel,,, and turns a 1000 +rpm more at 110k than the Falcon.40 years in the motortrade tends to destroy the fallacies made by the media and manufacturers! just like the stickers they put on everything that gives energy usage. Lies lies and more lies from fridges, washers and motorcars.

So called econo boxes often are not, and never will be. That is a fact of life but people always think that a 1.5 will use 1/4 the amount of petrol than a 4 litre. Which will never be the case as they will always be far less efficient. City driving a smaller engine will use less fuel ofcourse but probably 30% less, still making them very ineficient.Late 70s early 80s people went and bought 4 cyl familys cars, Sigmas, Coronas, Cortinas and the like. Then put autos and aircond etc. They used more petrol and carried less people comfortably than the full size Fords and Holdens etc.And were traded in again on full size cars in a year or two.And with the Daewoo, the family 4 with an auto, aircond and power steering pushing a big tall unairdynamic box is an asthmatic shit box and drinks fuel,,, and turns a 1000 +rpm more at 110k than the Falcon.40 years in the motortrade tends to destroy the fallacies made by the media and manufacturers! just like the stickers they put on everything that gives energy usage. Lies lies and more lies from fridges, washers and motorcars.

The fact remains that light cars with small engines use less fuel than heavy cars with large engines.

Designing the car around the standard parts is something they allready kinda do. VW Golf platform is a good example that gets used across different models. Same with their motors.

Standardisation is efficient.

Or should we reverse to when we had unice bolt/screw threads pr railroad company?

Im not talking about ONE type of hybrid unit. But a standard series kinda like when they have 1.6L to 2.5L options today.

Having standardised batteries or elements of the batteries. makes a recycle factory cheaper.

Lots of gains. Some challenges. The hybrid units will go trough a evolution like most others. The gain is that newer will probably be smaller and thus they will not be a challenge to fit in a older car.

Is standarisation (prob miss spelled) likely to such a high degree?

Naa. not likely. Companies allready cooperate across brands and the politicians would rather probably impose efficiency demands. Kinda like thee emissions we have today.

Efficiency demands could lead manufacturers down this ally. But regardless of option thats decades ahead if ever.

I guess I would ask how we calculate how much time, effort, resources, and ultimately $$$ we want to invest in a hybrid-retrofit system for the existing non-hybrid vehicles that have yet to be manufactured. You are making my head hurt a little.

I guess I would ask how we calculate how much time, effort, resources, and ultimately $$$ we want to invest in a hybrid-retrofit system for the existing non-hybrid vehicles that have yet to be manufactured. You are making my head hurt a little.

Its all opinions and arguments at this point, very little solid facts.

apart from following:

Standarisation is mostly efficient Free development is mostly efficient

back to your question.

I cut it down.

Time: Newer hybrid unit into a older hybrid car where both follow a standard would be a bolt on job = done in no time at all.

Effort? you mean time? se above, you mean resources? se below.

Resources: a few initial ones for the car manufacturers. but minimal once they are in play. Note that the standard should perhaps only cover the bolt holes/connections in the chassie and so on.

$$$: allmost the same as resources when you go big/global

Yes it is a fantasy but its a good one. Rather than individually modding mounts and so on every single car. Who i doubt few would bother with. blabla.